Sliding doors such as arcadia doors are widely used in homes, apartment buildings, and many commercial establishments, particularly for use as patio doors or the like. These doors offer the advantage of a wide expanse of glass and, since they do not swing inwardly or outwardly, do not intrude upon the space on either side of the door which then can be utilized in any manner desired. A disadvantage of such doors is that once they are opened, they require a positive effort to reclose. This is particularly disadvantageous for home owners with small children who typically forget it reclose the door after they open it and pass through it.
Door closers which automatically close sliding or arcadia doors have been developed to automatically reclose such doors after they have been opened. Most of these door closers are bulky and unattractive, so that they have not proved popular in home and apartment applications in particular.
A compact and effective sliding door closer which does not have the unslightly bulk of typical closers is disclosed in my prior U.S. Pat. No. 3,278,979 issued Oct. 18, 1966. While the closer disclosed in this patent effectively operates to automatically reclose sliding doors after they have been opened and permits a simple adjustment of the rate of closure, the locking of the door and maintaining the door in a partly open condition required the operation of a thumb screw. While the thumb screw was effective to accomplish the desired purpose, it was relatively inconvenient to use and did not provide as strong a lock for the door in the fully closed position as is now desirable.
Accordingly, it is desirable to provide an improved sliding door closer which may be securely locked in the closed position, operated with the automatic closer mechanism functioning, or operated as a normal sliding door without any action from the closer whatsoever. It is desirable that these three different modes of operation may be readily selected and controlled one to the other simply and effectively.